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中文核心期刊

固体颗粒在热对流下沉降的直接数值模拟研究

The study on the sedimentation of solid particle influenced by thermal convection using direct numerical simulation

  • 摘要: 在任意拉格朗日-欧拉算法模拟等温惰性颗粒两相流的基础上,增加对能量方程的联立求解,在热对流条件下对固体颗粒在不同雷诺数下的沉降规律进行了直接数值模拟.结果表明:热对流引起了流场流动的变化和不对称,颗粒在热流体中沉降,热对流产生的力加速了冷颗粒的运动,尾部形成了涡脱落;颗粒在冷流体中沉降,热对流产生的力阻碍了冷颗粒的运动,尾部形成了羽流. 随着雷诺数的增大,颗粒经历了稳定沉降、周期性摆动到不稳定、无规则运动3个阶段.

     

    Abstract: Based on the study of isothermal inert particlesedimentation, the Arbitrary Lagrangian-Eulerian technique was used to solvethe problem of solid particle sedimentation with thermal convectionincluding the energy equation, according to varying the solid-fluid densityratio, that is, the particles settle in different Reynolds number. Theresults show that the thermal convection induces the variety of flow fieldand asymmetry. While setting in hot fluid, the direction of thermalconvection is the same as that of particle sedimentation, and there arevortex shedding arisen by thermal convection. During the sedimentation ofhot particle in the cold fluid, the warm wake forms a strong upward thermalplume. With the increasing of Reynolds, the setting particles undergo threestages: steady motion with and without overshoot; weak and strongoscillations, and irregular oscillations.

     

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